1. Field of the Invention
This application is based upon and claims the benefit of priority from Japanese Patent Application No. 2010-254435, filed on Nov. 15, 2010, the disclosure of which is incorporated herein in its entirety by reference.
The present invention relates to a location-information discrimination system and, more particularly, to a method and device for discriminating among locations of a mobile terminal.
2. Description of the Related Art
There have been proposed various methods for determining whether a mobile terminal is located outdoors or indoors. According to indoors/outdoors determination methods using the Global Positioning System (GPS), an area that cannot be identified by the GPS is determined to be the indoors in many cases. Therefore, also proposed are indoors/outdoors determination methods using base stations of a mobile communication system in addition to the GPS.
For example, in an indoors/outdoors determination system disclosed in Japanese Patent Application Unexamined Publication No. 2007-232592 (JP2007-232592), a terminal acquires location information from each of the GPS and a mobile telephone base station (BS) and makes an indoors/outdoors determination in accordance with a determination rule based on such location information and the way of acquiring the location information, GPS/BS/GPS&BS.
Japanese Patent Application Unexamined Publication No. 2005-351823 (JP2005-351823) discloses a device that makes it possible to analyze the location of a terminal regardless of whether the terminal is located indoors or outdoors in such a manner that, with a wireless LAN location detection system being provided indoors, GPS location information and wireless LAN location information are integrated. Moreover, Japanese Patent Application Unexamined Publication No. 2008-005476 (JP2008-005476) discloses a method for estimating the location of a wireless terminal in such a manner that a probability distribution based on the electromagnetic characteristics of a signal from a base station is combined with a probability distribution based on the GPS.
In the above-mentioned indoors/outdoors determination system disclosed in JP2007-232592, indoors/outdoors determinations are made correspondingly to the three patterns of way of acquiring location information (that is, acquiring only from GPS, acquiring only from BS, and acquiring from both of GPS and BS). Therefore, the resolution of determination is coarse, and realistically, there are some cases where no right indoors/outdoors determination can be made.
Although JP2005-351823 and JP2008-005476 disclose the terminal location detection methods, these methods do not relate to indoors/outdoors determination. For example, according to JP2005-351823, since a wireless LAN location detection system needs to be provided indoors, the system configuration is complicated, and costs also rise. Additionally, it is impossible to perform terminal location detection itself in those buildings that are not provided with such an indoor system. Further, according to JP2008-005476, terminal location estimation is performed by utilizing the fact that the characteristics of an electromagnetic signal change depending on geographic features, the locations of a receiver and a sender, and the like. This is not an indoors/outdoors determination technology for a terminal.
Accordingly, with the methods taught by the above-mentioned patent literatures, it is difficult to always accurately determine the environment in which a terminal is located, such as the inside of an arcade or a building. Therefore, there are occasions when a provider providing advertisement information depending on the location of a terminal cannot provide appropriate information to users. Moreover, according to the above-mentioned patent literatures, the precision of determination is fixed, and it is impossible to make a determination in keeping with a situation.